Black men who have sex with men (BMSM) are disproportionately burdened with new and existing HIV infection. This is largely attributable to disparities in the HIV care continuum, a multistage care model that starts with diagnosis, is followed by linkage and retention in care, requires the prescription of and adherence to antiretroviral therapy (ART), and ends with viral suppression. Not only does the last stage represent control of HIV disease necessary for the health of individuals, it also makes possible the virtual elimination of sexual transmission of HIV infection to others; disparities in HIV treatment are disparities in HIV prevention. Supplementing behavioral data with information on CD4 count, ART use, and viral suppression are needed since these are biological markers of the care continuum that influence infection dynamics. We are currently collecting a random sample of BMSM attending Black Pride events (the Black Pride study, R01NR013865, PI: Stall) to understand factors associated with continuum disparities. Recent scientific advances suggest the need to enhance behavioral research with biological markers. Self-report may misclassify unknown HIV infection among BMSM; two studies demonstrate many who would have otherwise been classified as having unknown infection actually had detectable levels of ART or were virally suppressed. We may be inefficiently investing resources if diagnosis is not the continuum stage driving disparities. We must also explore the extent to which self-report may misclassify BMSM in other stages of the HIV care continuum. With these findings, and our theoretical framework, we hypothesize that the same factors that inhibit viral suppression (e.g., syndemic production, HIV stigma) are the same that influence discordance between self-report and biological data. We propose the use of dried blood spot (DBS) lab techniques to analyze CD4, ART, and viral load by collecting minute quantities of blood from BMSM. This study will address the following three Specific Aims:(1) Examine differences in operationalizing HIV care continuum position using self-report and biological data, (2) Explore HIV care continuum position and associated factors using a combination of behavioral and biological outcome data, and (3) Describe acceptability of using DBS in a community sample of BMSM. Completion of these aims will generate the most comprehensive understanding of the care continuum among BMSM to date, and will help inform best practices for research endeavors that seek to employ a combination of behavioral and biological data. This research will maximize intervention success for BMSM by allowing for the confident identification, and consequently the ability to target, sources of HIV disparities.